1. Field of the Invention
The invention is generally related to power tools such as line trimmers, leaf blowers, and the like, and, more particularly, to the means by which the operator holds the power tool during operation. Specifically, the invention is related to an arm engaging system which allows the movements of the power tool to be controlled at the operator's elbow, rather than his or her wrist. Furthermore, the invention includes certain improvements in wheeled platforms which are used on power line trimmers. The improvements in the arm engaging assembly and the wheeled platform facilitate the user's ability to perform sweeping movements during operation of a power line trimmer.
2. Description of the Prior Art
Power line trimmers and leaf blowers have become commonplace household tools in the suburban United States. Almost any hardware store of reasonable size will carry several different makes and models of power line trimmers and leaf blowers. During operation of this type of equipment a user generally sweeps the tool back and forth to accomplish his objective of either trimming grass and weeds or blowing leaves into a pile. Despite this common practice by consumers, producers of line trimmers and leaf blowers have failed to provide these devices with gripping assemblies which reduce user fatigue and facilitate performing sweeping movements. Rather, the handles for most commercially available power tools do not satisfactorily consider consumer ergonomics. Thus, operation of the tools becomes quickly fatiguing, and this results in reduced user satisfaction and less effective operation of the tool.
Currently, no power line trimmers are commercially available which employ a wheel assembly that contacts the ground during operation. Conversely, there are several patented line trimmer wheel assemblies (see, for example, U.S. Pat. No. 4,922,694 to Emoto, U.S. Pat. No. 4,287,709 to Lowery et al., U.S. Pat. No. 4,411,126 to Lowery et at., U.S. Pat. No. 4,756,147 to Savell, and U.S. Pat. No. 4,688,376 to Wolfe et al.). The lack of commercial development of these patented designs appears to be related to their complexity and to their inability to provide the user with an effective means for sweeping across weeds and grass in manner which most closely simulates operation of the line trimmer without the wheels.
More recently, Smith has disclosed in U.S. Pat. No. 5,287,683, a platform for a power line trimmer which includes a "sweep-lock" feature whereby wheels on opposite sides of the platform are locked into an orientation where they roll along lines which are offset from perpendicular to the pole or "shaft" of the line trimmer by equal and opposite angles. The Smith design provides an effective means for rolling the platform across the ground surface in a sweeping motion. Unfortunately, the handle design proposed in Smith is not ergonomically suited to most users and requires the user to be centrally located behind the platform and use both arms to both direct and sweep the platform. U.S. Pat. No. 5,287,683 to Smith also discloses a "track lock" feature which allows the wheels to roll along a straight line for edging purposes.